Power transmission aims to talk the torque!

The German manufacturer NCTE develops and manufactures in-line shaft sensors that measure torque and other forces such as shear and bending moment.

Available with full support in the UK from Ixthus Instrumentation, these directly mounted sensors are said to be especially practical for dynamic, high-precision load measurement of power transmission and power take-off (PTO) shafts where real-time data acquisition provides not just the safe operation of connected machinery, but also the ability to optimise efficiency and operation for the entire drive’s function.

NCTE sensors are designed to form part of the drive chain as a ‘plug and play’ component, complete with integrated signal conditioning and with no other components required. With several sized model options available, torque measurement, from a zero reference, can range from 1 to 10,000 Nm.

‘Magnetostriction’ in action

NCTE names its measurement technology ‘magnetostriction’, which is based on the magnetostrictive measurement principle. Simply put, this is a physical process where the length of a body changes under the influence of an external magnetic field. “By reversing this principle, NCTE’s sensors employ encoded magnetic fields and, as integral parts of the shaft, measure the miniscule dimensional changes directly induced on the driven shaft as torque or other physical forces,” states Ixthus. “This contactless, wear-free and low-maintenance technology tracks these changes in real time, with excellent stability over long periods of time.”

The sensors employ at least two opposed magnetic fields to allow error free use where external magnetic fields such as EMC interference are present – or where mechanical influences such as strong vibration and shock conditions cause shaft distortions. With standard protection class options of IP50 and IP65, the sensors can operate in high humidity, water, oils and aggressive liquids used, for instance, in washdown situations.

All the essentials

The sensors have a standard operating temperature range of -40 °C to +85 °C, a torque measurement accuracy in the region of +/- 0.5% and a shaft speeds range from 2,500 rpm for the larger sized models to 10,000 rpm for the smaller. Output frequency is 2,500 Hz with output options via a single electrical connector including 0 - 10 V, 4…20 mA, CANbus and USB; the USB interfaced models are supplied with free of charge PC software that enables direct data display via a GUI with the possibility to export data for detailed analysis.

NCTE’s custom design service is offered across all model ranges to facilitate use in extreme environments.

NCTE applies its torque measurement technology across all areas of industry and research from controlling the power of e-bikes to preventive maintenance on wind turbines, and from precision torque measurement for motorsports to safety monitoring on robotic and automated medical equipment.

Mobile agricultural machinery

A particular area that demonstrates the technology and applied use of NCTE’s PTO torque sensors is that of mobile agricultural machinery where power and torque and/or bending moment and shear measurement can be optimised. “Easily integrated between the PTO shaft of tractor and connected machinery such as powered harrows, spreaders, bailing presses etc, the sensors help to maintain the highest process efficiency and provide the basis for safe operation, maximum reliability, and preventive maintenance to avoid costly failures and repairs,” adds Ixthus

“In this application area, NCTE’s 7000 series torque sensors can measure bi-directional torque in the region of 3000 to 5000 Nm at speeds up to 3600 rpm. The 7000 series can be simply flange mounted or supplied with a wide choice of optional geared shaft and bush adapter that suit most common tractor, harvester and other farm machinery PTOs.” Test bench mounts are also available for research tasks.